The grading system of cs50x course checks whether your code is correct,properly indented, stylized in a way that it implements every loop,data structure,condition as per the syntax so, what you are asking is may be run time or space complexity or stuff that cs50 algos dont have to cover because there are almost n number of ways to implement to single pset of that course.So, if a you wanna implement it in the best possible way with regard to the parameters above then, that's something that requires peer review and possibly that is another task for every pset so, you may go for code review on stack exchange. CS50X doesn't incorporate any peer reviews because there are almost hundreds of thousands of people enrolled in that course and make them do peer review of one another is way not easy. So far as code reviews are considered, I think that using git hub gist is the best option as all your psets will be organized there and easy to access rather than copy and paste your code.
Hope this helps! And please put the check mark if this answer is apt,lets keep up on forum maintainance!